Coffee maker wakes up to steam

Bristol, UK -- Kraft Foods has fitted new steam traps to the feedwater heat exchangers, air heater batteries and distribution lines at its Banbury site, which house the world’s largest soluble coffee facility; producing some 11 billion cups of coffee a year for the global Kraft business as well as UK household brands such as Kenco, Maxwell House and Mellow Bird’s.

Kraft's plant raises some 40 tonnes of steam an hour costing around £6.5 million a year. Steam is used throughout the site, though principally in the feedwater heat exchangers feeding the extraction sets. The facility operates banks of heat exchangers, which handle a total of between 6,000 and 45,000 litres of water per hour.

Kraft Foods switched to Venturi orifice steam traps from Gardner Energy Management (GEM) after establishing that the existing mechanical traps were failing, resulting in lost steam and reduced plant performance. A total of 120 of the new devices are now being used throughout with site; operating over variable loads with a turndown ratio on the heat exchangers of 3:1.

The GEM steam traps work by using the difference in density between steam and condensate. Steam is 1000 times less dense than condensate, so at the entrance of the trap’s orifice, the low-density steam is squeezed out of the condensate. The high density, low moving condensate is then preferentially discharged through the orifice, trapping the low-density steam behind it.

The Venturi orifice configuration uses the ‘flash’ steam from the condensate as it passes from high to low pressure to give a self-regulating, varying capacity. The units have no moving parts to wedge open or fail, adds GEM.

“The GEM steam traps perform well over a wide range of loads”, said John Weir, utilities manager at Kraft Foods. “In addition to saving down time with maintenance and replacement traps, the GEM traps have provided us with a short term payback through energy savings from steam wastage.”